Method of and apparatus for making hollow rubber articles



1,625,398 Apnl 1927 J. SCHAEFER METHOD OF AND APPARATUS FOR MAKING HOLLOW RUBBER ARTICLES Filed April 16. 1925 3 Sheets-Sheet 1 1| Wu 1 m n E! 1* 1| k k I ZFVYENTOR J5 J6 g m fad/4% R E F E A H C 8 Im April 19,1927.

METHOD OF AND APPARATUS FOR MAKING HOLLOW RUBBER ARTICLES Filed April 16, 1923 I5 Sheets-Sheet 2 Jill ENTOR fly 7340/6 -ATTY5.

1,625,398 Apml 19, 1927. J. SCHAEFER METHOD OF AND APPARATUS FOR MAKING HOLLOW RUBBER ARTICLES Filed'April 16, 1923 '6 Sheets-SheetS IYYEBITOE j Patented. Apr. 19, 1927.

Unrran STATES PATENT OFFICE.

JAMES SCH.AEFER, OF WEST PATERSON, NEW JERSEY, ASSIGNOR TO PARAMOUNT RUBBER CONSOLIDATED. INC, OF LITTLE FALLS, NEW JERSEY, A CORPORATION OF DELAWARE.

METHOD OF AND APPARATUS FOR MAKING HOLLOW RUBBER ARTICLES.

Application filed April 16, 1923. Serial No. 632,281.

This invention relates to a method of and apparatus for making hollow rubber articles having certain portions or regions thereof offset from other portions or regions, such as rubber toy animals and similar ob- ]ects.

In making rubber toy objects, for instance, animals where there are legs off-set from a plane passing through the mid-portion of the animal, the usual practice heretofoie has been to form the opposing halves and then to cement the halves prior to vulcanization. One of the difliculties of joining two halves of a rubber toy animal in the vulcanizing process has been due to the fact that the body has usually been died out between male and female dies and semicured to hold its shape until vulcanized, and the semicuring interferes with satisfactorily securing the parts together. The operation is comparatively slow and expensive; Moreover the expense of matching male and female dies is considerable.

The object of my invention is to provide for pneumatically forming hollow rubber objects, of the character set forth, so as to eliminate the necessity for pressing the halves between male and female dies, and to enable economical and rapid operation.

I carry out the above object by using a forming mold so distorted that the different cavities therein terminate in one plane, so

that sheets of raw rubber may be laid acrossthe mold and pneumatically forced into the cavities and have their seams lying in the same plane; then the biscuit is transferred to a vulcanizing mold, the cavities of which a e formed and positioned according to the final object "to be produced. With such a forming mold,'I can surround each complete cavity bya raised cutting edge adapted to form an effective seam by mechanical pressure and also to cut 03 the surplus stock of raw material.

Another feature of the invention comprises making cooperating cavities in the two sections of the forming mold of different depth, whereby the rubber occupying one cavity is stretched to a greater degree than that occupying thecooperating cavity, and thus the normal tendency of the rubber. to

contract will deflect the portion-formed by' -tions p these cooperating cavities and enable it to be more readily positioned in-the vulcanizing mold. For example, in the manufacture of rubber toy animals, the cavities employed for the formation of the legs mav e of greater volume or depth in one section of the mold than in the cooperating section, whereby the rubber occupying the leg forming cavities is necessarily stretched more on one side than on the opposite side. As a result, the legs flare in the desired direction when the biscuit is removed from the mold, and this enables a biscuit. to occupy the cavities in the vulcanizing mold without undue distortion.

An apparatus for carrying oiit the above I invention includes both t e method and a paratus, and its essential features will summarized in the claims.

In the drawings, Fig. 1 is a plan view of a forming mold having cavities therein for the formation of an article representing a toy elephant; Fig. 2 is a section through the formin mold showin the cooperatin secl aced above eac other and also s owing the sheets of raw rubber stock across the faces of the sections; Fig.' 3 is a section through the mold with the'sections in roper juxtaposition for molding purposes; ig. 4 1s a bottom view of the biscuit; Fig. 5 is an end view of the biscuit shown in Fig. 4; Fig.. 6 is a diagram showing the relative proportions ofdepth in the'cooperating cavities of the forming mold to effect the flare of the legs in the biscuit; Fig. 7 is a plan view of the vulcanizing mold having the upper half removed and showing the biscuit in place; Fi 8 is a section taken on the line 8-8 in Fig. 7; Fig. 9 is a bottom view of the completed article; Fi 10 is a plan view of the vulcanizing mo d having the upper section removed and showing a modified form of article tobe; molded therein; Fig. 11 is a section taken on the lines 11-11 in Fig. 10; Figs. 12and' 13 are sections taken on the correspondingly numbered lines in Figs. 7 and 10 respectively (looking rearward in Fig. 7 and forwardin Fig. 10); and Fi obtained 14 is a bottom view of the object from the vulcanizin g mold shown plane. The various steps in ture of this toy article comprises the forms.

tion of a peculiar biscuit in the forming mold, then the transferring of the biscuit to a differently shaped vulcanizing mold against the wall of which the biscuit is ity 11 therein to form The step of forced by internal pressure.

he described.

forming the biscuit will now In Fig. 1, tionof a forming mold having a major car the body of an article, and having minor cavities the legs of the animal represented by the completed article, ity extends a raised cutting edge 10. Each section may be provided with an endless ways 1 6 in cavity in gheric groove 14: spaced inwardly 15,.which-leadto the base of. thejsection. Suitable passageways 17 providacommunication between the vacuum chamber and-the forming cavities as shown particularly in Figs. 2 and3. The top section is similar in construction to the bottom section. so far as the major cavity and vacuum groove is concerned, so that each section forms one-half the body of the article to be formed. The conduits 9 may be connected to a suitable vacuum pump (not shown) for exhausting the air n the vacuum chamber and thereby to draw the raw rubher stock into the'cavities. 5 1

The arrangement ofthe minor cavities in the cooperating sections is designed-to cause the portions of the article formed in the; mi 101 cavities to he flared when the biscuit is removed from the forming mold.- To ob-l tain this result, the minor cavity in one section' is larger than the cooperating minor the other section as shown particularly in Figs. 2 and 3. Thus, the cavities 12 are larger in the top section than the cavities 13, while in the lower section, the

cavities 13 are larger than the cavities 12' Accordingly, when sheets of raw rubber stock A. and B are placed across the sections 1 and 2 of the forming mold, and the atmospressure in the chambers 16 is reneed so as to cause the sheets of rubber to conforinto the cavities in the sections, then the rubber in the cavities as much as the rubber in the coo crating cavities 12 in the upper section. imilarly, the rubber in the top thereof lying in another the manufac- I have illustrated the lower secgram 1] ustratmg the arrangement of co 12 and 13 to form and around the entire cav-.

from the mar ginal edges of theseotion, and with passe e-:

a'vacuumcham' r while. in Fig.

vulcanizing operatlon: the leg portions are shown as being otl'sct'j.

dicate 12 on the lower secrubber is to assume the original position which causes the legs 12" and 13' to flare in opposite directions so that the seams of the rubher'which comprise the leg portions, are

moved out of the general plane passing through the meeting edges of the body portion. Accordingly, when thebiscuit is placed in the vulcanizing mold, the legs partially occupy the minor cavities wherefore the vulcanized article is formed without distor-, tion of the rubber adjacent the region of connection between the body portion and leg portions. I InFi fi,'Ihave-'showngraphically a diaoperating' cavities-to cause the mid-plane throu h the le portions to deviate from the mid-p ane of t iebody portion when the hiscuit is removed from the forming mold. In this diagram, the lineC indicates the midplane passing through the body portion while t e curved lines 12" and 13, respectively, indicate the rubber occupying the small minor cavities, while the curved lines 12 and 13 indicate the stretched rubber which occupies the large minor cavities. The arrows then indicate the direction in which the rubber occupying the minor cavities is flared when the biscuit is removed from the mold.

The'next step in the formation ofa hol-i 7, I have shown the lower section 3 of a vu canizing mold f with the biscuit in place,.

' 8 I have shown the two sec:

tions 3 and 4 in proper junta )osition for the In t iis last, figure, 1

from the mid-plane of the body portion. wherefore the completed articles as indicated in Fig. 9 represents a toy in natural osition. During the vulcanization, the ru her is held against the walls of the vulcanizing mold due to the internal pressure resultin from the usual expansihle substance in the biscuit during the forming operation. The oiiset relationship of the minor cavity to the'major cavity in the vul-, canizing mold is shown more clearly in Figs. 12 and 13 which re resent sections in the correspondinglynum red lines in Figs. 7 and 10 res ectively, looking in the directions in by the arrows.

From t is foregoingdescription it'will be seen that my invention is the formation pneumatically from sheet stock of hollow rubber articles representing v animal standing well adapted for;

"' *neaasasit toy animals, wherein the planes passing. through the leg portions are notthe same' as the planes assing through the seam fthe body portion. It will further be seen that hollow rubber articles having these. 'charaeteristicsmay thus be made with only 7 forming and vulcanizing operations, that the cost is greatly reduced over theold-dieing. process, and -1e speed of production greatly increased. Y Having thus described my invention, I claim 11 1. The method of articles comprising bringing together two parts with the meetingedges thereof lying in a singleplane and then vulcanizing the parts with the'meeting edges lying: a

plurality of plane.

2. The method of forming hollow rubber" articles comprising the seating of stock. in two mold cavities eacl" surrounded by a cutting edge lying 'inone 'plane', bringing such-mold cavities togethci' to join the parts and shear oil the surplus stock, and vulcanizing the biscuit with its meeting edges in a plurality of planes. Y

3. The method of forming hollow rubber articles comprising pneumatically seating articles comprising pneumatically seatin r'f' raw rubber stock in torminglinolds having a cavity surrounded"byia cuttingedge terminating in one planeyand:thenivul canizing the art1cIe-withthe abutting'ledges' of sheet rubber comprising'placing'isheet rubber stock in forming molds with the abutting edges of. the stock'in' one plane and, thereafter, vulcanizing'the article with the abutting edges of one port-ion in one "plane and the abutting edges of another portion in another plane. v p

l. The method of forming hollow rubber of one portion in Ton'e plane, and the abutting edges ot another portion inianother plane, 1

5., The method of making hollowarticles stock across the mouths of mold cavities having their edges in a plane, seating such stock by suction applied to the' cavities,

joining the seated stock, removing it from" the forming moldand'tinally vulcanizing it with its meeting-edges inn: plurality'of lanes. 6. The method of forming. hollow rubber articles comprisin" seating rubber stock in 1 a forming mold ravingv minor-and minor-s cavities so arranged that the abutting edges he inone'plane. and then' vulcanizing the article so that the portions formed in the minor cavities'have their-meeting edges in a plane difie'rent 'fromthat-passing through the abutting edges of the parts formed in the major cavities. 1

7. The method-of forming hollow rubber .yarticles comprising pneumatically seating sheet rubber stock in a forming mold in. ma or and minor cavit es so arranged that forming hollow; rubber-'1'" ,10. -The apparatus all thejabutting lie in one plane and thenvulcanizing the article so that the per tions formed-in the minor cavities have their meeting edges in a plane different fromthat passing through the abutting edges of the parts formed in the major cavities.

hollow rub- -8.' An apparatus for formmg ber articles comprising a forming mold, one

of the cavities in one section of the forming v mold having greater volume than the'co operating cavities in the other section of the forming mold, wherefore the rubber occupy- Y ing the deeper of such cavities isfstrctched mo1"e' than the rubber occupying the cooperatingcavity, therefor, and a vulcanizing 1nold. liavi1 1g cavities of similar depthflinl the two mold sections.

1 9, Tl 1e apparatus for forming hollow rubher articles comprising means for pneumati cally seating sheet rubber stock in major and nuuorcavities in a forming mold, the minor cav ties in one section of: the forming mold having greater volume than the cooperating minor cavity in the other section of the forming mold wherefore the rubber occupymore than the rubber occupying. the cooperating cavity.

portion lying 'i n' -one plane', and the'ijuncplane,- comprising means for I forforming -hollow rubber -arhcles hav ngthejunction of one.

: ing the deeper-minor cavity is stretched -'tion of another -'portion' lying' in another seating-rubber- 'stock-, i-n a orming mold having Teavities therein, the avities in one v ioo section-,having greater volume than the -co operating 1 cavities in the other .,sectionf,- wherefore the rubberoccupymgthe-dee )er- .cavity -ii's stretched morel than the rub r -.oecupying ,the cooperating cavities sothat the normaltndency of the-stretched rubber toeontract causes the plane.passingthrough 1 the junction "of such portion to deviate froin plane passing tl1ro'ugh the .ijunction 9f: 0. r 11'. The appar tusfforfformin hollow] another portion.

rubber articles having the seams' one por-.

tion ;lying in one-plane an'dithefseams of deeper Icavityis stretched more than the rubber. occupying the cooperatin cavities so a it is stretched 5 that the normal tendency of.

-rubber to contract causes the'plane' passing through the seam of such portion to deviatel i from a plane passing through the seam'of" another portion.

12. .The fapparatusaforaiming? hollow rubber articles comprising means, for: seat;

Ill

All

mg rubber Stutll. in forming molds having comuumicaling cavities, one pair of cooperating cavities being of substantially equal wine in the two mold sections and another pair of cooperating cavities being of unequal size in the two mold sections, Wheretore a portion of the article formed by the rubber stock has unequal volumes on oppositcsidcs oi the plane passing through the abutting edges of said stock and a cooperating vulcanizing mold having substantially equal reacting cavities.

13. In an apparatus for forming hollow rubber articles the combination of means for pneumatically seating raw rubber stock in forming molds having major and minor cavities, the major cavities being of substantially equal size'in the cooperating mold sections. and the minor cavities being of unct ual size in the cooperating mold sections, wherefore the article formed by the rubber stock has unequal volumes on opposite sides or": a plane passing through the abutting edges of said stock and a cooperating vulcaniaing mold.

ll. In an apparatus for l'naking hollow rubber articles, a forming mold having major and, minor cavities in the cooperating mold sections, the cavities being of such depth that the-rubber occupying the major cavities is stretched substantially equally in the cooperating mold sections, while the rubber occupying the minor cavities is stretched unequally in the cooperating mold sections.

Jan apparatus for use in the method of making hollow rubber articles comprising means for seating sheet rubber stock by suclion in a forming mold having major and minor cavities in the cooperating mold sections, the cavities being of such depth that the rubber occupying the major cavities is stretched equally in the cooperating mold sections, while the rubber occupying the minor cavities is stretched unequally in the cooperating mold sections Wherefore the porlltlllfi formed in the minor cavities are flared when the biscuit is removed from the forming mold.

ltl. An a liparatus for making hollow rubber articles comprising means for seating of raw rubber stock in cooperating sections of forming molds, said sections having major and minor cavities so formed that the rubber occupying the major cavities is stretched substantially equally in the cooperating sections while the rubber occupying the'minor mivities is stretched unequally in the coop crating :iections Wherefore the portions of tin: article termed therein are flared in opposite directions when the biscuit is retrieved lrom the mold, and a cooperating vulcaniraing mold wherein the minor sections are placed in cavities otlset from the general meeting plane in the. direction of the flare.

ll. an apparatus for making hollow rubeas es ber articles comprising a forming mold having its meeting faces in one plane and a cooperating vulcanizing mold having its meeting faces in different planes.

18. An apparatus for making hollowrubber articles comprising a forming mold having its cavities surrounded by cutting edges terminating in a plane and a cooperating vulcanizing mold having the meeting faces of its corresponding cavities in different planes.

19. An apparatus for making hollow rubber articles comprising the combination of a forming mold having its cavities surrounded by a cutting edge terminating in a plane, means for exhausting air from each cavity, and a vulcanizing mold having an ollset meeting face and having its cavities a proximately corresponding to those of tie forming mold but ditl'erently positioned therefrom.

'20. An apparatus for forming hollow rubber articles comprising a pair of forming mold sections having major and minor cavities therein, but the n'ieeting edges of all of said cavities lying in the same plane, and a cooperating vulcanizing mold having the meeting edges of the major cavities in one plane and those of the minor cavities in other planes.

21. An ILpPdlZltLlS for forming hollow rubber articles comprising a pair of mold tions having major cavities and minor cavities, the cooperating major cavities being of substantially equal size and the cooperating minor cavities being of unilqual size.

22. An apparatus for forming hollow rubber articles comprising a pair of forming mold sections having major and minor cavities-therein, the cooperating major cavities in said sections being of substantially equal size and the cooperating minor cavities in said sections being of unequal size, the meeting edges of all of said cavities lying in the same plane and comprising a raised cutting edge. I j

23. The method of forming hollow rubber articles comprising taking two sheets ol rub her, outwardly bulging them in certain re-- gions, one )air of cooperating bulges being substantial y equal and another pair being unequal in the respective sheets, and then oining the sheets together by a continuous seam extending about the equal'and unequal bulges successively.

24. The method of forming hollow rubber articles comprising pneumatically seating two sheets of rubber in such manner that in one region the rubber is stretched differently in one mold member from the other While in another region the relative stretching in the two mold members is more nearly identical.

25. The method of forming hollow rubber articles comprising pneumatically seating two sheets of rubber in such manner that in one region the ratio of stretching of the rubber in the opposed parts is different from the ratio of stretching of the rubber in the opposed parts-in another region.

stretching, whereby the legs tend to flare the body of a biscuit with the the direction of the greater 2.7. The method of making hollow rubber articles havinga. plurality of legs comprising forming the biscuit in such manner that the legs flare apart and then vulcanizing the article in a manner which maintains the legs substantially parallel.

stretching, and then vulcanizing the body and legs as a unit.

11 testimony whereof, I hereunto afiix my 20 signature.

JAMES SCHAEFER. 

